Comparative study of carbonized peach shell and carbonized apricot shell to improve the performance of lightweight concrete

To improve the performance of peach shell concrete (PSC) and apricot shell concrete (ASC), the effect of carbonized peach shell (CPS) and carbonized apricot shell (CAS) instead of peach shell (PS) and apricot shell (AS), respectively, on physical, mechanical and triaxial creep properties of lightweight aggregate concrete (LWAC) was investigated. Results showed that the replacement of raw aggregates (PS and AS) with carbonized aggregates (CPS and CAS) reduced the density, water absorption and open porosity, and increased the efficiency factor, total porosity of LWAC. Moreover, the mechanical properties were significantly enhanced, and the CAS mixture obtained the highest compressive strength, splitting tensile strength, flexural strength and modulus of elasticity, which were 38.8 MPa, 3.54 MPa, 5.49 MPa, and 15.1 GPa, respectively, an increase of 44.2%, 55.3%, 54.6%, and 42.5%, respectively, compared to the AS mixture. Triaxial creep results showed that under coupled water pressure and axial pressure condition, the use of carbonized aggregates instead of raw aggregates significantly decreased creep strain of LWAC and the concentrations of K+, Ca2+, Na+, Mg2+ and Sr2+ in the leaching solution. Therefore, use of CPS and CAS as lightweight aggregate in concrete can significantly improve the performance of LWAC.